1. Field of the Invention
The inventive concept relates to a field-programmable gate array (FPGA), and more particularly, to a programmable logic block of a FPGA.
2. Description of the Related Art
A field-programmable gate array (FPGA) is an electronic component that has a particular function due to its programming by a user even if the function thereof is not fixed when the FPGA is manufactured, and is a kind of programmable logic device (PLD). The FPGA represents reconfigurable large-scale integrated circuits (LSI). In the case of the FPGA, its usage is expanded to portable applications such as digital apparatuses, for example, plasma display panels (PDPs) and liquid-crystal display televisions LCD TVs etc., camcorders, and Blue-ray disks due to continuous development of its performance and reduction in its manufacturing cost.
The FPGA includes a programmable logic block (circuit), for example, a programmable switch device that can program a logic gate or a logic block by the user's programming through an interconnection wire. That is, in the FPGA, a programmable logic block (circuit) as a programmable switch device is included to reconfigure a portion of the LSI circuit. The programmable logic block (circuit) of the FPGA uses a switch circuit that is configured of a static random access memory (SRAM) or a flip-flop and a pass-gate.
The programmable logic block, that is, a switch circuit, not only occupies a significantly large area but also reduces an operation speed due to the increase in parasitic components. Thus, in spite of high manufacturing costs, its application range is very limited. In order to overcome the limitation of the operation speed of the reconfigurable LSI circuit and to reduce the costs for manufacturing chips, it is essential to improve the programmable logic block (circuit).